Demi Moore and Ashton Kutcher are happy because they don't think about the future.

The 46-year-old actress and her 31-year-old husband believe they have a successful marriage because they are grateful for the time they spend together and try never to look beyond the present.

When asked what the secret to her happy relationship was, Demi replied: “I think that’s too big of a question to take on right now. I like to look at where I am in the present moment as being the highlight.”

Despite trying not to plan for the future, Demi – who has three daughter with ex-husband Bruce Willis – recently admitted she and Ashton have discussed having children of their own one day.

She said: "Why not? Everything is possible! We have so much to live for, and obviously one of them is to have a child. I'm very enthusiastic about all the possibilities that living together gives us.  

"I'm an incurable optimist and a go-getter - it's in my nature to focus much more on what makes me happy than what makes me nervous."